Apparatus for Use with Needle Insertion Guidance System

ABSTRACT

A guidance system utilizes ultrasound imaging or other suitable imaging technology. In one embodiment, the guidance system includes an imaging device including a probe for producing an image of an internal body portion target, such as a vessel. One or more sensors may be associated with the probe. The system may include a medical device, such as a needle, separate from the probe, the medical device having a magnetic field associated therewith. The system may include a processor that uses data relating to the magnetic field sensed by the one or more sensors to determine a position and/or orientation of the medical device. The system may also include a display that shows an image of the internal body portion target taken by the ultrasound imaging probe and a depiction of the medical device positioned and/or oriented with respect to the image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/118,138, filed May 27, 2011, which is a continuation-in-part of U.S.patent application Ser. No. 13/118,033, filed May 27, 2011, which is acontinuation-in-part of U.S. patent application Ser. No. 12/323,273,filed Nov. 25, 2008. This application claims the benefit of thefollowing provisional applications either directly or via one or more ofthe parent applications: U.S. Provisional Application No. 61/349,771,filed May 28, 2010, U.S. Provisional Application No. 61/095,921, filedSep. 10, 2008, U.S. Provisional Application No. 61/095,451, filed Sep.9, 2008, U.S. Provisional Application No. 61/091,233, filed Aug. 22,2008, U.S. Provisional Application No. 61/054,944, filed Apr. 17, 2008,and U.S. Provisional Application No. 60/990,242, filed Nov. 26, 2007.Each of the aforementioned applications is incorporated herein byreference in its entirety.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed toan integrated catheter placement system configured for accuratelyplacing a catheter within the vasculature of a patient. The integratedsystem employs at least two modalities for improving catheter placementaccuracy: 1) ultrasound-assisted guidance for introducing the catheterinto the patient's vasculature; and 2) a tip location system (“TLS”), ormagnetically-based (e.g., via permanent magnet(s) or electromagnet(s))tracking of the catheter tip during its advancement through thevasculature to detect and facilitate correction of any tip malpositionduring such advancement.

In one embodiment, the integrated system comprises a system consoleincluding a control processor, a tip location sensor for temporaryplacement on a portion of a body of the patient, and an ultrasoundprobe. The tip location sensor senses a magnetic field of a styletdisposed in a lumen of the catheter when the catheter is disposed in thevasculature. The ultrasound probe ultrasonically images a portion of thevasculature prior to introduction of the catheter into the vasculature.In addition, the ultrasound probe includes user input controls forcontrolling use of the ultrasound probe in an ultrasound mode and use ofthe tip location sensor in a tip location mode.

In another embodiment, a third modality, i.e., ECG signal-based cathetertip guidance, is included in the system to enable guidance of thecatheter tip to a desired position with respect to a node of thepatient's heart from which the ECG signals originate.

In addition, embodiments of the present disclosure are also directed toa guidance system for assisting with the insertion of a needle or othermedical component into the body of a patient. The guidance systemutilizes ultrasound imaging or other suitable imaging technology.

In one embodiment, the guidance system comprises an imaging deviceincluding a probe for producing an image of an internal body portiontarget, such as a subcutaneous vessel, for instance. One or more sensorsare included with the probe. The sensors sense a detectablecharacteristic related to the needle, such as a magnetic field of amagnet included with the needle.

The system includes a processor that uses data relating to thedetectable characteristic sensed by the sensors to determine a positionand/or orientation of the needle in three spatial dimensions. The systemincludes a display for depicting the position and/or orientation of theneedle together with the image of the target.

In addition to magnet-based detection, other modalities for detectingthe medical component are disclosed, including optically-based andelectromagnetic signal-based systems.

In one embodiment, a stylet including one or more magnetic elements isremovably inserted into the needle to enable tracking of the needle viadetection of the magnetic elements by a sensor included with theultrasound probe. In one embodiment, the sensor is a ring sensordisposed about a portion of the ultrasound probe. In another embodiment,the stylet can additionally include a strain sensor that detects bendingof the needle during insertion into the patient. Feedback from thestrain sensor can be input into the system and accounted for in order tomore accurately depict needle location on the display.

In yet another embodiment, the magnetic element is configured as adonut-shaped passive magnet defining a hole through which the cannula ofthe needle passes.

These and other features of embodiments of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of embodiments of theinvention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the present disclosure will be renderedby reference to specific embodiments thereof that are illustrated in theappended drawings. It is appreciated that these drawings depict onlytypical embodiments of the invention and are therefore not to beconsidered limiting of its scope. Example embodiments of the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a block diagram depicting various elements of an integratedsystem for intravascular placement of a catheter, according to oneexample embodiment of the present invention;

FIG. 2 is a simplified view of a patient and a catheter being insertedtherein with assistance of the integrated system of FIG. 1;

FIGS. 3A and 3B are views of a probe of the integrated system of FIG. 1;

FIG. 4 is a screenshot of an ultrasound image as depicted on a displayof the integrated system of FIG. 1;

FIG. 5 is a perspective view of a stylet employed in connection with thesystem of FIG. 1 in placing a catheter within a patient vasculature;

FIG. 6 is an icon as depicted on a display of the integrated system ofFIG. 1, indicating a position of a distal end of the stylet of FIG. 5during catheter tip placement procedures;

FIGS. 7A-7E depict various example icons that can be depicted on thedisplay of the integrated system of FIG. 1 during catheter tip placementprocedures;

FIGS. 8A-8C are screenshots of images depicted on a display of theintegrated system of FIG. 1 during catheter tip placement procedures;

FIG. 9 is a block diagram depicting various elements of an integratedsystem for intravascular placement of a catheter, according to anotherexample embodiment of the present invention;

FIG. 10 is a simplified view of a patient and a catheter being insertedtherein with assistance of the integrated system of FIG. 9;

FIG. 11 is a perspective view of a stylet employed in connection withthe integrated system of FIG. 9 in placing a catheter within a patientvasculature;

FIGS. 12A-12E are various views of portions of the stylet of FIG. 11;

FIGS. 13A-13D are various views of a fin connector assembly for use withthe integrated system of FIG. 9;

FIGS. 14A-14C are views showing the connection of a stylet tether andfin connector to a sensor of the integrated system of FIG. 9;

FIG. 15 is a cross sectional view of the connection of the stylettether, fin connector, and sensor shown in FIG. 14C;

FIG. 16 is simplified view of an ECG trace of a patient;

FIG. 17 is a screenshot of an image depicted on a display of theintegrated system of FIG. 9 during catheter tip placement procedures;

FIG. 18 is a block diagram depicting various elements of anultrasound-based guidance system for needles and other medicalcomponents, according to one embodiment;

FIG. 19 is a simplified view of a patient and a catheter being insertedtherein, showing one possible environment in which the guidance systemof FIG. 18 can be practiced;

FIG. 20 is a top view of the ultrasound probe of the guidance system ofFIG. 18;

FIG. 21A is a side view of a needle for use with the guidance system ofFIG. 18, according to one embodiment;

FIG. 21B is an end view of the needle of FIG. 21A;

FIGS. 22A and 22B are simplified views of the ultrasound probe of theguidance system being used to guide a needle toward a vessel within thebody of a patient;

FIGS. 23A and 23B show possible screenshots for depiction on the displayof the guidance system, showing the position and orientation of a needleaccording to one embodiment;

FIG. 24 shows various stages of a method for guiding a needle to adesired target within the body of a patient according to one embodiment;

FIG. 25 shows a sensor array for attachment to an ultrasound probe andassociated display, according to one embodiment;

FIG. 26 is a simplified view of a needle holder gun for use with theguidance system of FIG. 18, according to one embodiment;

FIG. 27 is a simplified view of an ultrasound probe and needle includingelements of an optical guidance system, according to one embodiment;

FIG. 28 shows operation of the ultrasound probe and needle of FIG. 27,according to one embodiment;

FIG. 29 is a simplified view of an ultrasound probe and needle includingelements of an electromagnetic signal-based guidance system, accordingto one embodiment;

FIG. 30 is a simplified view of an ultrasound probe and needle includingelements of an electromagnetic signal-based guidance system, accordingto another embodiment;

FIGS. 31A-31D are various views of a needle and associated componentsfor use with a needle guidance system, according to one embodiment;

FIG. 32 is a side view of a needle for use with a needle guidancesystem, according to one embodiment;

FIGS. 33A and 33B are various views of a needle for use with a needleguidance system, according to one embodiment;

FIGS. 34A-34G are views of variously shaped magnetic elements for usewith a needle guidance system according to one embodiment;

FIG. 35 is a perspective view of a distal portion of a needle cannulaincluding a magnet-bearing stylet disposed therein, according to oneembodiment;

FIG. 36 shows the needle of FIG. 35 in use with an ultrasound probeincluding a ring sensor, according to one embodiment;

FIG. 37 is a perspective view of a needle including a donut magnetdisposed on the cannula, according to one embodiment;

FIG. 38 is a side view of a stylet including a strain gauge according toone embodiment;

FIGS. 39A-39B show the stylet and strain gauge of FIG. 38 under bendingstress; and

FIG. 40 is a side view of a stylet including a flex sensor according toone embodiment.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exemplaryembodiments of the present invention, and are neither limiting nornecessarily drawn to scale.

For clarity it is to be understood that the word “proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of a needleplaced within the body of a patient is considered a distal end of theneedle, while the needle end remaining outside the body is a proximalend of the needle. Also, the words “including,” “has,” and “having,” asused herein, including the claims, shall have the same meaning as theword “comprising.”

I. Assisted Catheter Placement

Embodiments of the present invention are generally directed to acatheter placement system configured for accurately placing a catheterwithin the vasculature of a patient. In one embodiment, the catheterplacement system employs at least two modalities for improving catheterplacement accuracy: 1) ultrasound-assisted guidance for introducing thecatheter into the patient's vasculature; and 2) a tiplocation/navigation system (“TLS”), or magnetically-based tracking ofthe catheter tip during its advancement through the tortuous vasculaturepath to detect and facilitate correction of any tip malposition duringsuch advancement. The ultrasound guidance and tip location features ofthe present system according to one embodiment are integrated into asingle device for use by a clinician placing the catheter. Integrationof these two modalities into a single device simplifies the catheterplacement process and results in relatively faster catheter placements.For instance, the integrated catheter placement system enablesultrasound and TLS activities to be viewed from a single display of theintegrated system. Also, controls located on an ultrasound probe of theintegrated device, which probe is maintained within the sterile field ofthe patient during catheter placement, can be used to controlfunctionality of the system, thus precluding the need for a clinician toreach out of the sterile field in order to control the system.

In another embodiment, a third modality, i.e., ECG signal-based cathetertip guidance, is included in the integrated system to enable guidance ofthe catheter tip to a desired position with respect to a node of thepatient's heart from which the ECG signals originate. Such ECG-basedpositional assistance is also referred to herein as “tip confirmation.”

Combination of the three modalities above according to one embodimentenables the catheter placement system to facilitate catheter placementwithin the patient's vasculature with a relatively high level ofaccuracy, i.e., placement of the distal tip of the catheter in apredetermined and desired position. Moreover, because of the ECG-basedguidance of the catheter tip, correct tip placement may be confirmedwithout the need for a confirmatory X-ray. This, in turn, reduces thepatient's exposure to potentially harmful x-rays, the cost and timeinvolved in transporting the patient to and from the x-ray department,costly and inconvenient catheter repositioning procedures, etc.

Reference is first made to FIGS. 1 and 2 which depict various componentsof a catheter placement system (“system”), generally designated at 10,configured in accordance with one example embodiment of the presentinvention. As shown, the system 10 generally includes a console 20,display 30, probe 40, and sensor 50, each of which is described infurther detail below.

FIG. 2 shows the general relation of these components to a patient 70during a procedure to place a catheter 72 into the patient vasculaturethrough a skin insertion site 73. FIG. 2 shows that the catheter 72generally includes a proximal portion 74 that remains exterior to thepatient and a distal potion 76 that resides within the patientvasculature after placement is complete. The system 10 is employed toultimately position a distal tip 76A of the catheter 72 in a desiredposition within the patient vasculature. In one embodiment, the desiredposition for the catheter distal tip 76A is proximate the patient'sheart, such as in the lower one-third (⅓^(rd)) portion of the SuperiorVena Cava (“SVC”). Of course, the system 10 can be employed to place thecatheter distal tip in other locations. The catheter proximal portion 74further includes a hub 74A that provides fluid communication between theone or more lumens of the catheter 72 and one or more extension legs 74Bextending proximally from the hub.

An example implementation of the console 20 is shown in FIG. 8C, thoughit is appreciated that the console can take one of a variety of forms. Aprocessor 22, including non-volatile memory such as EEPROM for instance,is included in the console 20 for controlling system function duringoperation of the system 10, thus acting as a control processor. Adigital controller/analog interface 24 is also included with the console20 and is in communication with both the processor 22 and other systemcomponents to govern interfacing between the probe 40, sensor 50, andother system components.

The system 10 further includes ports 52 for connection with the sensor50 and optional components 54 including a printer, storage media,keyboard, etc. The ports in one embodiment are USB ports, though otherport types or a combination of port types can be used for this and theother interfaces connections described herein. A power connection 56 isincluded with the console 20 to enable operable connection to anexternal power supply 58. An internal battery 60 can also be employed,either with or exclusive of an external power supply. Power managementcircuitry 59 is included with the digital controller/analog interface 24of the console to regulate power use and distribution.

The display 30 in the present embodiment is integrated into the console20 and is used to display information to the clinician during thecatheter placement procedure. In another embodiment, the display may beseparate from the console. As will be seen, the content depicted by thedisplay 30 changes according to which mode the catheter placement systemis in: US, TLS, or in other embodiments, ECG tip confirmation. In oneembodiment, a console button interface 32 (see FIGS. 1, 8C) and buttonsincluded on the probe 40 can be used to immediately call up a desiredmode to the display 30 by the clinician to assist in the placementprocedure. In one embodiment, information from multiple modes, such asTLS and ECG, may be displayed simultaneously, such as in FIG. 17. Thus,the single display 30 of the system console 20 can be employed forultrasound guidance in accessing a patient's vasculature, TLS guidanceduring catheter advancement through the vasculature, and (as in laterembodiments) ECG-based confirmation of catheter distal tip placementwith respect to a node of the patient's heart. In one embodiment, thedisplay 30 is an LCD device.

FIGS. 3A and 3B depict features of the probe 40 according to oneembodiment. The probe 40 is employed in connection with the firstmodality mentioned above, i.e., ultrasound (“US”)-based visualization ofa vessel, such as a vein, in preparation for insertion of the catheter72 into the vasculature. Such visualization gives real time ultrasoundguidance for introducing the catheter into the vasculature of thepatient and assists in reducing complications typically associated withsuch introduction, including inadvertent arterial puncture, hematoma,pneumothorax, etc.

The handheld probe 40 includes a head 80 that houses a piezoelectricarray for producing ultrasonic pulses and for receiving echoes thereofafter reflection by the patient's body when the head is placed againstthe patient's skin proximate the prospective insertion site 73 (FIG. 2).The probe 40 further includes a plurality of control buttons 84, whichcan be included on a button pad 82. In the present embodiment, themodality of the system 10 can be controlled by the control buttons 84,thus eliminating the need for the clinician to reach out of the sterilefield, which is established about the patient insertion site prior tocatheter placement, to change modes via use of the console buttoninterface 32.

As such, in one embodiment a clinician employs the first (US) modalityto determine a suitable insertion site and establish vascular access,such as with a needle or introducer, then with the catheter. Theclinician can then seamlessly switch, via button pushes on the probebutton pad 82, to the second (TLS) modality without having to reach outof the sterile field. The TLS mode can then be used to assist inadvancement of the catheter 72 through the vasculature toward anintended destination.

FIG. 1 shows that the probe 40 further includes button and memorycontroller 42 for governing button and probe operation. The button andmemory controller 42 can include non-volatile memory, such as EEPROM, inone embodiment. The button and memory controller 42 is in operablecommunication with a probe interface 44 of the console 20, whichincludes a piezo input/output component 44A for interfacing with theprobe piezoelectric array and a button and memory input/output component44B for interfacing with the button and memory controller 42.

FIG. 4 shows an example screenshot 88 as depicted on the display 30while the system 10 is in its first ultrasound modality. An image 90 ofa subcutaneous region of the patient 70 is shown, depicting a crosssection of a vein 92. The image 90 is produced by operation of thepiezoelectric array of the probe 40, also included on the displayscreenshot 88 is a depth scale indicator 94, providing informationregarding the depth of the image 90 below the patient's skin, a lumensize scale 96 that provides information as to the size of the vein 92relative to standard catheter lumen sizes, and other indicia 98 thatprovide information regarding status of the system 10 or possibleactions to be taken, e.g., freeze frame, image templates, data save,image print, power status, image brightness, etc.

Note that while a vein is depicted in the image 90, other body lumens orportions can be imaged in other embodiments. Note that the US mode shownin FIG. 4 can be simultaneously depicted on the display 30 with othermodes, such as the TLS mode, if desired. In addition to the visualdisplay 30, aural information, such as beeps, tones, etc., can also beemployed by the system 10 to assist the clinician during catheterplacement. Moreover, the buttons included on the probe 40 and theconsole button interface 32 can be configured in a variety of ways,including the use of user input controls in addition to buttons, such asslide switches, toggle switches, electronic or touch-sensitive pads,etc. Additionally, both US and TLS activities can occur simultaneouslyor exclusively during use of the system 10.

As just described, the handheld ultrasound probe 40 is employed as partof the integrated catheter placement system 10 to enable USvisualization of the peripheral vasculature of a patient in preparationfor transcutaneous introduction of the catheter. In the present exampleembodiment, however, the probe is also employed to control functionalityof the TLS portion, or second modality, of the system 10 when navigatingthe catheter toward its desired destination within the vasculature asdescribed below. Again, as the probe 40 is used within the sterile fieldof the patient, this feature enables TLS functionality to be controlledentirely from within the sterile field. Thus the probe 40 is adual-purpose device, enabling convenient control of both US and TLSfunctionality of the system 10 from the sterile field. In oneembodiment, the probe can also be employed to control some or allECG-related functionality, or third modality, of the catheter placementsystem 10, as described further below.

The catheter placement system 10 further includes the second modalitymentioned above, i.e., the magnetically-based catheter TLS, or tiplocation system. The TLS enables the clinician to quickly locate andconfirm the position and/or orientation of the catheter 72, such as aperipherally-inserted central catheter (“PICC”), central venous catheter(“CVC”), or other suitable catheter, during initial placement into andadvancement through the vasculature of the patient 70. Specifically, theTLS modality detects a magnetic field generated by a magneticelement-equipped tip location stylet, which is pre-loaded in oneembodiment into a longitudinally defined lumen of the catheter 72, thusenabling the clinician to ascertain the general location and orientationof the catheter tip within the patient body. In one embodiment, themagnetic assembly can be tracked using the teachings of one or more ofthe following U.S. Pat. Nos. 5,775,322; 5,879,297; 6,129,668; 6,216,028;and 6,263,230. The contents of the afore-mentioned U.S. patents areincorporated herein by reference in their entireties. The TLS alsodisplays the direction in which the catheter tip is pointing, thusfurther assisting accurate catheter placement. The TLS further assiststhe clinician in determining when a malposition of the catheter tip hasoccurred, such as in the case where the tip has deviated from a desiredvenous path into another vein.

As mentioned, the TLS utilizes a stylet to enable the distal end of thecatheter 72 to be tracked during its advancement through thevasculature. FIG. 5 gives an example of such a stylet 100, whichincludes a proximal end 100A and a distal end 100B. A handle is includedat the stylet proximal end 100A, with a core wire 104 extending distallytherefrom. A magnetic assembly is disposed distally of the core wire104. The magnetic assembly includes one or more magnetic elements 106disposed adjacent one another proximate the stylet distal end 100B andencapsulated by tubing 108. In the present embodiment, a plurality ofmagnetic elements 106 is included, each element including a solid,cylindrically shaped ferromagnetic stacked end-to-end with the othermagnetic elements. An adhesive tip 110 can fill the distal tip of thetubing 108, distally to the magnetic elements 106.

Note that in other embodiments, the magnetic elements may vary from thedesign in not only shape, but also composition, number, size, magnetictype, and position in the stylet distal segment. For example, in oneembodiment, the plurality of ferromagnetic magnetic elements is replacedwith an electromagnetic assembly, such as an electromagnetic coil, whichproduces a magnetic field for detection by the sensor. Another exampleof an assembly usable here can be found in U.S. Pat. No. 5,099,845,titled “Medical Instrument Location Means,” which is incorporated hereinby reference in its entirety. Yet other examples of stylets includingmagnetic elements that can be employed with the TLS modality can befound in U.S. Patent Application Publication No. 2007/0049846, filedAug. 23, 2006, titled “Stylet Apparatuses and Methods of Manufacture,”which is incorporated herein by reference in its entirety. These andother variations are therefore contemplated by embodiments of thepresent invention. It should appreciated herein that “stylet” as usedherein can include any one of a variety of devices configured forremovable placement within a lumen of the catheter to assist in placinga distal end of the catheter in a desired location within the patient'svasculature.

FIG. 2 shows disposal of the stylet 100 substantially within a lumen inthe catheter 72 such that the proximal portion thereof extendsproximally from the catheter lumen, through the hub 74A and out througha selected one of the extension legs 74B. So disposed within a lumen ofthe catheter, the distal end 100B of the stylet 100 is substantiallyco-terminal with the distal catheter end 76A such that detection by theTLS of the stylet distal end correspondingly indicates the location ofthe catheter distal end.

The TLS sensor 50 is employed by the system 10 during TLS operation todetect a magnetic field produced by the magnetic elements 106 of thestylet 100. As seen in FIG. 2, the TLS sensor 50 is placed on the chestof the patient during catheter insertion. The TLS sensor 50 is placed onthe chest of the patient in a predetermined location, such as throughthe use of external body landmarks, to enable the magnetic field of thestylet magnetic elements 106, disposed in the catheter 72 as describedabove, to be detected during catheter transit through the patientvasculature. Again, as the magnetic elements 106 of the stylet magneticassembly are co-terminal with the distal end 76A of the catheter 72(FIG. 2), detection by the TLS sensor 50 of the magnetic field of themagnetic elements provides information to the clinician as to theposition and orientation of the catheter distal end during its transit.

In greater detail, the TLS sensor 50 is operably connected to theconsole 20 of the system 10 via one or more of the ports 52, as shown inFIG. 1. Note that other connection schemes between the TLS sensor andthe system console can also be used without limitation. As justdescribed, the magnetic elements 106 are employed in the stylet 100 toenable the position of the catheter distal end 76A (FIG. 2) to beobservable relative to the TLS sensor 50 placed on the patient's chest.Detection by the TLS sensor 50 of the stylet magnetic elements 106 isgraphically displayed on the display 30 of the console 20 during TLSmode. In this way, a clinician placing the catheter is able to generallydetermine the location of the catheter distal end 76A within the patientvasculature relative o the TLS sensor 50 and detect when cathetermalposition, such as advancement of the catheter along an undesiredvein, is occurring.

FIGS. 6 and 7A-7E show examples of icons that can be used by the consoledisplay 30 to depict detection of the stylet magnetic elements 106 bythe TLS sensor 50. In particular, FIG. 6 shows an icon 114 that depictsthe distal portion of the stylet 100, including the magnetic elements106 as detected by the TLS sensor 50 when the magnetic elements arepositioned under the TLS sensor. As the stylet distal end 100B issubstantially co-terminal with the distal end 76A of the catheter 72,the icon indicates the position and orientation of the catheter distalend. FIGS. 7A-7E show various icons that can be depicted on the on theconsole display 30 when the magnetic elements 106 of the stylet 100 arenot positioned directly under a portion of the TLS sensor 50, but arenonetheless detected nearby. The icons can include half-icons 114A andquarter-icons 114B that are displayed according to the position of thestylet magnetic assembly, i.e., the magnetic elements 106 in the presentembodiment, relative to the TLS sensor 50.

FIGS. 8A-8C depict screenshots taken from the display 30 of the system10 while in TLS mode, showing how the magnetic assembly of the stylet100 is depicted. The screenshot 118 of FIG. 8A shows a representativeimage 120 of the TLS sensor 50. Other information is provided on thedisplay screenshot 118, including a depth scale indicator 124,status/action indicia 126, and icons 128 corresponding to the buttoninterface 32 included on the console 20 (FIG. 8C). Though the icons 128in the present embodiment are simply indicators to guide the user inidentifying the purpose of the corresponding buttons of the buttoninterface 32, in another embodiment the display can be madetouch-sensitive so that the icons themselves can function as buttoninterfaces and can change according to the mode the system is in.

During initial stages of catheter advancement through the patient'svasculature after insertion therein, the distal end 76A of the catheter72, having the stylet distal end 100B substantially co-terminaltherewith, is relatively distant from the TLS sensor 50. As such, thedisplay screenshot will indicate “no signal,” indicating that themagnetic field from the stylet magnetic assembly has not been detected.In FIG. 8B, the magnetic assembly proximate the stylet distal end 100Bhas advanced sufficiently close to the TLS sensor 50 to be detectedthereby, though it is not yet under the sensor. This is indicated by thehalf-icon 114A shown to the left of the sensor image 120, representingthe stylet magnetic assembly being positioned to the right of the TLSsensor 50 from the perspective of the patient.

In FIG. 8C, the magnetic assembly proximate the stylet distal end 100Bhas advanced under the TLS sensor 50 such that its position andorientation relative thereto is detected by the TLS sensor. This isindicated by the icon 114 on the sensor image 120. Note that the buttonicons 128 provide indications of the actions that can be performed bypressing the corresponding buttons of the console button interface 32.As such, the button icons 128 can change according to which modality thesystem 10 is in, thus providing flexibility of use for the buttoninterface 32. Note further that, as the button pad 82 of the probe 40(FIGS. 3A, 3B) includes buttons 84 that mimic several of the buttons ofthe button interface 32, the button icons 128 on the display 30 providea guide to the clinician for controlling the system 10 with the probebuttons 84 while remaining in the sterile field. For instance, if theclinician has need to leave TLS mode and return to US (ultrasound) mode,the appropriate control button 84 on the probe button pad 82 can bedepressed, and the US mode can be immediately called up, with thedisplay 30 refreshing to accommodate the visual information needed forUS functionality, such as that shown in FIG. 4. This is accomplishedwithout a need for the clinician to reach out of the sterile field.

Reference is now made to FIGS. 9 and 10 in describing the integratedcatheter placement system 10 according to another example embodiment. Asbefore, the integrated system 10 includes the console 20, display 30,probe 40 for US functionality, and the TLS sensor 50 for tip locationfunctionality as described above. Note that the system 10 depicted inFIGS. 9 and 10 is similar in many respects to the system shown in FIGS.1 and 2. As such, only selected differences will be discussed below. Thesystem 10 of FIGS. 9 and 10 includes additional functionality whereindetermination of the proximity of the catheter distal tip 76A relativeto a sino-atrial (“SA”) or other electrical impulse-emitting node of theheart of the patient 70 can be determined, thus providing enhancedability to accurately place the catheter distal tip in a desiredlocation proximate the node. Also referred to herein as “ECG” or“ECG-based tip confirmation,” this third modality of the system 10enables detection of ECG signals from the SA node in order to place thecatheter distal tip in a desired location within the patientvasculature. Note that the US, TLS, and ECG modalities are seamlesslycombined in the present system 10 and can be employed in concert orindividually to assist in catheter placement.

FIGS. 9 and 10 show the addition to the system 10 of a stylet 130configured in accordance with the present embodiment. As an overview,the catheter stylet 130 is removably predisposed within the lumen of thecatheter 72 being inserted into the patient 70 via the insertion site73. The stylet 130, in addition to including a magnetic assembly for themagnetically-based TLS modality, includes an ECG sensor assemblyproximate its distal end and including a portion that is co-terminalwith the distal end of the catheter tip for sensing ECG signals producedby the SA node. In contrast to the previous embodiment, the stylet 130includes a tether 134 extending from its proximal end that operablyconnects to the TLS sensor 50. As will be described in further detail,the stylet tether 134 permits ECG signals detected by the ECG sensorassembly included on a distal portion of the stylet 130 to be conveyedto the TLS sensor 50 during confirmation of the catheter tip location aspart of the ECG signal-based tip confirmation modality. Reference andground ECG lead/electrode pairs 158 attach to the body of the body ofthe patient 70 and are operably attached to the TLS sensor 50 to enablethe system to filter out high level electrical activity unrelated to theelectrical activity of the SA node of the heart, thus enabling theECG-based tip confirmation functionality. Together with the referenceand ground signals received from the ECG lead/electrode pairs 158 placedon the patient's skin, the ECG signals sensed by the stylet ECG sensorassembly are received by the TLS sensor 50 positioned on the patient'schest (FIG. 10). The TLS sensor 50 and/or console processor 22 canprocess the ECG signal data to produce an electrocardiogram waveform onthe display 30, as will be described. In the case where the TLS sensor50 processes the ECG signal data, a processor is included therein toperform the intended functionality. If the console 20 processes the ECGsignal data, the processor 22, controller 24, or other processor can beutilized in the console to process the data.

Thus, as it is advanced through the patient vasculature, the catheter 72equipped with the stylet 130 as described above can advance under theTLS sensor 50, which is positioned on the chest of the patient as shownin FIG. 10. This enables the TLS sensor 50 to detect the position of themagnetic assembly of the stylet 130, which is substantially co-terminalwith the distal tip 76A of the catheter as located within the patient'svasculature. The detection by the TLS sensor 50 of the stylet magneticassembly is depicted on the display 30 during ECG mode. The display 30further depicts during ECG mode an ECG electrocardiogram waveformproduced as a result of patient heart's electrical activity as detectedby the ECG sensor assembly of the stylet 130. In greater detail, the ECGelectrical activity of the SA node, including the P-wave of thewaveform, is detected by the ECG sensor assembly of the stylet(described below) and forwarded to the TLS sensor 50 and console 20. TheECG electrical activity is then processed for depiction on the display30. clinician placing the catheter can then observe the ECG data todetermine optimum placement of the distal tip 76A of the catheter 72,such as proximate the SA node in one embodiment. In one embodiment, theconsole 20 which includes the electronic components, such as theprocessor 22 (FIG. 9) necessary to receive and process the signalsdetected by the stylet ECG sensor assembly. In another embodiment, theTLS sensor 50 can include the necessary electronic components processingthe ECG signals.

As already discussed, the display 30 is used to display information tothe clinician during the catheter placement procedure. The content ofthe display 30 changes according to which mode the catheter placementsystem is in: US, TLS, or ECG. Any of the three modes can be immediatelycalled up to the display 30 by the clinician, and in some casesinformation from multiple modes, such as TLS and ECG, may be displayedsimultaneously. In one embodiment, as before, the mode the system is inmay be controlled by the control buttons 84 included on the handheldprobe 40, thus eliminating the need for the clinician to reach out ofthe sterile field (such as touching the button interface 32 of theconsole 20) to change modes. Thus, in the present embodiment the probe40 is employed to also control some or all ECG-related functionality ofthe system 10. Note that the button interface 32 or other inputconfigurations can also be used to control system functionality. Also,in addition to the visual display 30, aural information, such as beeps,tones, etc., can also be employed by the system to assist the clinicianduring catheter placement.

Reference is now made to FIGS. 11-12E in describing various details ofone embodiment of the stylet 130 that is removably loaded into thecatheter 72 and employed during insertion to position the distal tip 76Aof the catheter in a desired location within the patient vasculature. Asshown, the stylet 130 as removed from the catheter defines a proximalend 130A and a distal end 130B. A connector 132 is included at theproximal stylet end 130A, and a tether 134 extends distally from theconnector and attaches to a handle 136. A core wire 138 extends distallyfrom the handle 136. The stylet 130 is pre-loaded within a lumen of thecatheter 72 in one embodiment such that the distal end 130B issubstantially flush, or co-terminal, with the catheter opening at thedistal end 76A thereof (FIG. 10), and such that a proximal portion ofthe core wire 138, the handle 136, and the tether 134 extend proximallyfrom a selected one of the extension tubes 74B. Note that, thoughdescribed herein as a stylet, in other embodiments a guidewire or othercatheter guiding apparatus could include the principles of theembodiment described herein.

The core wire 138 defines an elongate shape and is composed of asuitable stylet material including stainless steel or a memory materialsuch as, in one embodiment, a nickel and titanium-containing alloycommonly known by the acronym “nitinol.” Though not shown here,manufacture of the core wire 138 from nitinol in one embodiment enablesthe portion of the core wire corresponding to a distal segment of thestylet to have a pre-shaped bent configuration so as to urge the distalportion of the catheter 72 into a similar bent configuration. In otherembodiments, the core wire includes no pre-shaping. Further, the nitinolconstruction lends torqueability to the core wire 138 to enable a distalsegment of the stylet 130 to be manipulated while disposed within thelumen of the catheter 72, which in turn enables the distal portion ofthe catheter to be navigated through the vasculature during catheterinsertion.

The handle 136 is provided to enable insertion/removal of the styletfrom the catheter 72. In embodiments where the stylet core wire 138 istorqueable, the handle 136 further enables the core wire to be rotatedwithin the lumen of the catheter 72, to assist in navigating thecatheter distal portion through the vasculature of the patient 70.

The handle 136 attaches to a distal end of the tether 134. In thepresent embodiment, the tether 134 is a flexible, shielded cable housingone or more conductive wires electrically connected both to the corewire 138, which acts as the ECG sensor assembly referred to above, andthe tether connector 132. As such, the tether 134 provides a conductivepathway from the distal portion of the core wire 138 through to thetether connector 132 at proximal end 130A of the stylet 130. As will beexplained, the tether connector 132 is configured for operableconnection to the TLS sensor 50 on the patient's chest for assisting innavigation of the catheter distal tip 76A to a desired location withinthe patient vasculature.

As seen in FIGS. 12B-12D, a distal portion of the core wire 138 isgradually tapered, or reduced in diameter, distally from a junctionpoint 142. A sleeve 140 is slid over the reduced-diameter core wireportion. Though of relatively greater diameter here, the sleeve inanother embodiment can be sized to substantially match the diameter ofthe proximal portion of the stylet core wire. The stylet 130 furtherincludes a magnetic assembly disposed proximate the distal end 130Bthereof for use during TLS mode. The magnetic assembly in theillustrated embodiment includes a plurality of magnetic elements 144interposed between an outer surface of the reduced-diameter core wire138 and an inner surface of the sleeve 140 proximate the stylet distalend 130B. In the present embodiment, the magnetic elements 144 include20 ferromagnetic magnets of a solid cylindrical shape stacked end-to-endin a manner similar to the stylet 100 of FIG. 2. In other embodiments,however, the magnetic element(s) may vary from this design in not onlyshape, but also composition, number, size, magnetic type, and positionin the stylet. For example, in one embodiment the plurality of magnetsof the magnetic assembly is replaced with an electromagnetic coil thatproduces a magnetic field for detection by the TLS sensor. These andother variations are therefore contemplated by embodiments of thepresent invention.

The magnetic elements 144 are employed in the stylet 130 distal portionto enable the position of the stylet distal end 130B to be observablerelative to the TLS sensor 50 placed on the patient's chest. As has beenmentioned, the TLS sensor 50 is configured to detect the magnetic fieldof the magnetic elements 144 as the stylet advances with the catheter 72through the patient vasculature. In this way, a clinician placing thecatheter 72 is able to generally determine the location of the catheterdistal end 76A within the patient vasculature and detect when cathetermalposition is occurring, such as advancement of the catheter along anundesired vein, for instance.

The stylet 130 further includes the afore-mentioned ECG sensor assembly,according to one embodiment. The ECG sensor assembly enables the stylet130, disposed in a lumen of the catheter 72 during insertion, to beemployed in detecting an intra-atrial ECG signal produced by an SA orother node of the patient's heart, thereby allowing for navigation ofthe distal tip 76A of the catheter 72 to a predetermined location withinthe vasculature proximate the patient's heart. Thus, the ECG sensorassembly serves as an aide in confirming proper placement of thecatheter distal tip 76A.

In the embodiment illustrated in FIGS. 11-12E, the ECG sensor assemblyincludes a distal portion of the core wire 138 disposed proximate thestylet distal end 130B. The core wire 138, being electricallyconductive, enables ECG signals to be detected by the distal end thereofand transmitted proximally along the core wire. A conductive material146, such as a conductive epoxy, fills a distal portion of the sleeve140 adjacent the distal termination of the core wire 138 so as to be inconductive communication with the distal end of the core wire. This inturn increases the conductive surface of the distal end 130B of thestylet 130 so as to improve its ability to detect ECG signals.

Before catheter placement, the stylet 130 is loaded into a lumen of thecatheter 72. Note that the stylet 130 can come preloaded in the catheterlumen from the manufacturer, or loaded into the catheter by theclinician prior to catheter insertion. The stylet 130 is disposed withinthe catheter lumen such that the distal end 130B of the stylet 130 issubstantially co-terminal with the distal tip 76A of the catheter 72,thus placing the distal tips of both the stylet and the catheter insubstantial alignment with one another. The co-terminality of thecatheter 72 and stylet 130 enables the magnetic assembly to functionwith the TLS sensor 50 in TLS mode to track the position of the catheterdistal tip 76A as it advances within the patient vasculature, as hasbeen described. Note, however, that for the tip confirmationfunctionality of the system 10, the distal end 130B of the stylet 130need not be co-terminal with the catheter distal end 76A. Rather, allthat is required is that a conductive path between the vasculature andthe ECG sensor assembly, in this case the core wire 138, be establishedsuch that electrical impulses of the SA node or other node of thepatient's heart can be detected. This conductive path in one embodimentcan include various components including saline solution, blood, etc.

In one embodiment, once the catheter 72 has been introduced into thepatient vasculature via the insertion site 73 (FIG. 10) the TLS mode ofthe system 10 can be employed as already described to advance thecatheter distal tip 76A toward its intended destination proximate the SAnode. Upon approaching the region of the heart, the system 10 can beswitched to ECG mode to enable ECG signals emitted by the SA node to bedetected. As the stylet-loaded catheter is advanced toward the patient'sheart, the electrically conductive ECG sensor assembly, including thedistal end of the core wire 138 and the conductive material 146, beginsto detect the electrical impulses produced by the SA node. As such, theECG sensor assembly serves as an electrode for detecting the ECGsignals. The elongate core wire 138 proximal to the core wire distal endserves as a conductive pathway to convey the electrical impulsesproduced by the SA node and received by the ECG sensor assembly to thetether 134.

The tether 134 conveys the ECG signals to the TLS sensor 50 temporarilyplaced on the patient's chest. The tether 134 is operably connected tothe TLS sensor 50 via the tether connector 132 or other suitable director indirect connective configuration. As described, the ECG signal canthen be process and depicted on the system display 30 (FIGS. 9, 10).Monitoring of the ECG signal received by the TLS sensor 50 and displayedby the display 30 enables a clinician to observe and analyze changes inthe signal as the catheter distal tip 76A advances toward the SA node.When the received ECG signal matches a desired profile, the cliniciancan determine that the catheter distal tip 76A has reached a desiredposition with respect to the SA node. As mentioned, in one embodimentthis desired position lies within the lower one-third (⅓_(rd)) portionof the SVC.

The ECG sensor assembly and magnetic assembly can work in concert inassisting a clinician in placing a catheter within the vasculature.Generally, the magnetic assembly of the stylet 130 assists the clinicianin generally navigating the vasculature from initial catheter insertionso as to place the distal end 76A of the catheter 72 in the generalregion of the patient's heart. The ECG sensor assembly can then beemployed to guide the catheter distal end 76A to the desired locationwithin the SVC by enabling the clinician to observe changes in the ECGsignals produced by the heart as the stylet ECG sensor assemblyapproaches the SA node. Again, once a suitable ECG signal profile isobserved, the clinician can determine that the distal ends of both thestylet 130 and the catheter 72 have arrived at the desired location withrespect to the patient's heart. Once it has been positioned as desired,the catheter 72 may be secured in place and the stylet 130 removed fromthe catheter lumen. It is noted here that the stylet may include one ofa variety of configurations in addition to what is explicitly describedherein. In one embodiment, the stylet can attach directly to the consoleinstead of an indirect attachment via the TLS sensor. In anotherembodiment, the structure of the stylet 130 that enables its TLS andECG-related functionalities can be integrated into the catheterstructure itself. For instance, the magnetic assembly and/or ECG sensorassembly can, in one embodiment, be incorporated into the wall of thecatheter.

FIGS. 13A-15 describe various details relating to the passage of ECGsignal data from the stylet tether 134 to the TLS sensor 50 positionedon the patient's chest, according the present embodiment. In particular,this embodiment is concerned with passage of ECG signal data from asterile field surrounding the catheter 72 and insertion site 73, whichincludes the stylet 130 and tether 134, and a non-sterile field, such asthe patient's chest on which the TLS sensor is positioned. Such passageshould not disrupt the sterile field so that the sterility thereof iscompromised. A sterile drape that is positioned over the patient 70during the catheter insertion procedure defines the majority of thesterile field: areas above the drape are sterile, while areas below(excluding the insertion site and immediately surrounding region) arenon-sterile. As will be seen, the discussion below includes at least afirst communication node associated with the stylet 130, and a secondcommunication node associated with the TLS sensor 50 that operablyconnect with one another to enable ECG signal data transfertherebetween.

One embodiment addressing the passage of ECG signal data from thesterile field to the non-sterile field without compromising thesterility of the former is depicted in FIGS. 13A-15, which depict a“through-drape” implementation also referred to as a “shark fin”implementation. In particular, FIG. 14A shows the TLS sensor 50 asdescribed above for placement on the chest of the patient during acatheter insertion procedure. The TLS sensor 50 includes on a topsurface thereof a connector base 152 defining a channel 152A in whichare disposed three electrical base contacts 154. A fin connector 156,also shown in FIGS. 13A-13D, is sized to be slidingly received by thechannel 152A of the connector base 152, as shown in FIGS. 14B and 15.Two ECG lead/electrode pairs 158 extend from the fin connector 156 forplacement on the shoulder and torso or other suitable external locationson the patient body. The drape-piercing tether connector 132 isconfigured to slidingly mate with a portion of the fin connector 156, aswill be described further below, to complete a conductive pathway fromthe stylet 120, through the sterile field to the TLS sensor 50.

FIGS. 13A-13D show further aspects of the fin connector 156. Inparticular, the fin connector 156 defines a lower barrel portion 160that is sized to be received in the channel 152A of the connector base152 (FIGS. 14B, 15). A hole 162 surrounded by a centering cone 164 isincluded on a back end of an upper barrel portion 166. The upper barrelportion 166 is sized to receive the tether connector 132 of the stylet130 (FIGS. 14C, 15) such that a pin contact 170 extending into a channel172 of the tether connector 132 (FIG. 15) is guided by the centeringhole until it seats within the hole 162 of the fin connector 156, thusinterconnecting the tether connector with the fin connector. Anengagement feature, such as the engagement feature 169 shown in FIGS.13C and 13D, can be included on the fin connector 156 to engage with acorresponding feature on the tether connector 132 to assist withmaintaining a mating between the two components.

FIG. 13D shows that the fin connector 156 includes a plurality ofelectrical contacts 168. In the present embodiment, three contacts 168are included: the two forward-most contact each electrically connectingwith a terminal end of one of the ECG leads 158, and the rear contactextending into axial proximity of the hole 162 so as to electricallyconnect with the pin contact 170 of the tether connector 132 when thelatter is mated with the fin connector 156 (FIG. 15). A bottom portionof each contact 168 of the fin connector 156 is positioned toelectrically connect with a corresponding one of the base contacts 154of the TLS sensor connector base 152.

FIG. 14B shows a first connection stage, wherein the fin connector 156is removably mated with the TLS sensor connector base 152 by the slidingengagement of the lower barrel portion 160 of the fin connector with theconnector base channel 152A. This engagement electrically connects theconnector base contacts 154 with the corresponding fin contacts 168.

FIG. 14C shows a second connection stage, wherein the tether connector132 is removably mated with the fin connector 156 by the slidingengagement of the tether connector channel 172 with the upper barrelportion 166 of the fin connector. This engagement electrically connectsthe tether connector pin contact 170 with the back contact 168 of thefin connector 156, as best seen in FIG. 15. In the present embodiment,the horizontal sliding movement of the tether connector 132 with respectto the fin connector 156 is in the same engagement direction as when thefin connector is slidably mated to the sensor connector base channel152A (FIG. 14B). In one embodiment, one or both of the stylet 130/tetherconnector 132 and the fin connector 156 are disposable. Also, the tetherconnector in one embodiment can be mated to the fin connector after thefin connector has been mated to the TLS sensor, while in anotherembodiment the tether connector can be first mated to the fin connectorthrough the surgical drape before the fin connector is mated to the TLSsensor.

In the connection scheme shown in FIG. 14C, the stylet 130 is operablyconnected to the TLS sensor 50 via the tether connector 132, thusenabling the ECG sensor assembly of the stylet to communicate ECGsignals to the TLS sensor. In addition, the ECG lead/electrode pairs 158are operably connected to the TLS sensor 50. In one embodiment,therefore, the tether connector 132 is referred to as a firstcommunication node for the stylet 130, while the fin connector 156 isreferred to as a second communication node for the TLS sensor 50.

Note that various other connective schemes and structures can beemployed to establish operable communication between the stylet and theTLS sensor. For instance, the tether connector can use a slicing contactinstead of a pin contact to pierce the drape. Or, the fin connector canbe integrally formed with the TLS sensor. These and other configurationsare therefore embraced within the scope of embodiments of the presentdisclosure.

As seen in FIG. 15, a sterile drape 174 used during catheter placementto establish a sterile field is interposed between the interconnectionof the tether connector 132 with the fin connector 156. As justdescribed, the tether connector 132 includes the pin contact 170 that isconfigured to pierce the drape 174 when the two components are mated.This piercing forms a small hole, or perforation 175, in the steriledrape 174 that is occupied by the pin contact 170, thus minimizing thesize of the drape perforation by the pin contact. Moreover, the fitbetween the tether connector 132 and the fin connector 156 is such thatthe perforation in sterile drape made by piercing of the pin contact 170is enclosed by the tether connector channel 172, thus preserving thesterility of the drape and preventing a breach in the drape that couldcompromise the sterile field established thereby. The tether connectorchannel 172 is configured so as to fold the sterile drape 174 down priorto piercing by the pin contact 170 such that the pin contact does notpierce the drape until it is disposed proximate the hole 162 of the finconnector 156. It is noted here that the tether connector 132 and finconnector 156 are configured so as to facilitate alignment therebetweenblindly through the opaque sterile drape 174, i.e., via palpation absentvisualization by the clinician of both components.

Note further that the fin contacts 168 of the fin connector 156 as shownin FIG. 15 are configured to mate with the sensor base contacts 154 insuch a way as to assist in retaining the fin connector in engagementwith the sensor base channel 152A. This in turn reduces the need foradditional apparatus to secure the fin connector 156 to the TLS sensor50.

FIG. 16 shows a typical ECG waveform 176, including a P-wave and a QRScomplex. Generally, the amplitude of the P-wave varies as a function ofdistance of the ECG sensor assembly from the SA node, which produces thewaveform 176. A clinician can use this relationship in determining whenthe catheter tip is properly positioned proximate the heart. Forinstance, in one implementation the catheter tip is desirably placedwithin the lower one-third (⅓_(rd)) of the superior vena cava, as hasbeen discussed. The ECG data detected by the ECG sensor assembly of thestylet 130 is used to reproduce waveforms such as the waveform 176, fordepiction on the display 30 of the system 10 during ECG mode.

Reference is now made to FIG. 17 in describing display aspects of ECGsignal data on the display 30 when the system 10 is in ECG mode, thethird modality described further above, according to one embodiment. Thescreenshot 178 of the display 30 includes elements of the TLS modality,including a representative image 120 of the TLS sensor 50, and can theicon 114 corresponding to the position of the distal end of the stylet130 during transit through the patient vasculature. The screenshot 178further includes a window 180 in which the current ECG waveform capturedby the ECG sensor assembly of the stylet 130 and processed by the system10 is displayed. The window 180 is continually refreshed as newwaveforms are detected.

Window 182 includes a successive depiction of the most recent detectedECG waveforms, and includes a refresh bar 182A, which moves laterally torefresh the waveforms as they are detected. Window 184A is used todisplay a baseline ECG waveform, captured before the ECG sensor assemblyis brought into proximity with the SA node, for comparison purposes toassist the clinician in determining when the desired catheter tiplocation has been achieved. Windows 184B and 184C can be filed byuser-selected detected ECG waveforms when the user pushes apredetermined button on the probe 40 or the console button interface 32.The waveforms in the windows 184B and 184C remain until overwritten bynew waveforms as a result of user selection via button pushes or otherinput. As in previous modes, the depth scale 124, status/action indicia126, and button icons 128 are included on the display 30. An integrityindicator 186 is also included on the display 30 to give an indicationof whether the ECG lead/electrode pairs 158 are operably connected tothe TLS sensor 50.

As seen above, therefore, the display 30 depicts in one embodimentelements of both the TLS and ECG modalities simultaneously on a singlescreen, thus offering the clinician ample data to assist in placing thecatheter distal tip in a desired position. Note further that in oneembodiment a printout of the screenshot or selected ECG or TLS data canbe saved, printed, or otherwise preserved by the system 10 to enabledocumentation of proper catheter placement.

Although the embodiments described herein relate to a particularconfiguration of a catheter, such as a PICC or CVC, such embodiments aremerely exemplary. Accordingly, the principles of the present inventioncan be extended to catheters of many different configurations anddesigns.

II. Assisted Guidance for Needle/Medical Component

Embodiments of the present invention described herein are generallydirected to a guidance system for locating and guiding a needle or othermedical component during ultrasound-based or other suitable proceduresfor accessing with the needle a subcutaneous vessel of a patient, forinstance. In one embodiment, the guidance system enables the position,orientation, and advancement of the needle to be superimposed inreal-time atop the ultrasound image of the vessel, thus enabling aclinician to accurately guide the needle to the intended target.Furthermore, in one embodiment, the guidance system tracks the needle'sposition in five degrees of motion: x, y, and z spatial coordinatespace, needle pitch, and needle yaw. Such tracking enables the needle tobe guided and placed with relatively high accuracy.

Reference is first made to FIGS. 18 and 19, which depict variouscomponents of an ultrasound-based needle guidance system (“system”),generally designated at 1110, configured in accordance with oneembodiment of the present invention. As shown, the system 1110 generallyincludes an ultrasound (“US”) imaging portion including a console 1120,display 1130, and probe 1140, each of which is described in furtherdetail below. Note that the system 1110 bears similarity to the system10 shown in FIG. 1 with respect to some components, in one embodiment.It should be noted, however, that the ultrasound imaging portion can beconfigured in one of a variety of ways in addition to what is shown anddescribed herein.

The ultrasound imaging portion of the system 1110 is employed to image atargeted internal portion of a body of a patient prior to percutaneousinsertion of a needle or other device to access the target. As describedbelow, in one embodiment insertion of the needle is performed prior tothe subsequent insertion of a catheter into a vein or other portion ofthe vasculature of the patient. It is appreciated, however, thatinsertion of a needle into the body of a patient can be performed for avariety of medical purposes.

FIG. 19 shows the general relation of the above-described components toa patient 1170 during a procedure to ultimately place a catheter 1172into the patient vasculature through a skin insertion site 1173,according to one embodiment. FIG. 19 shows that the catheter 1172generally includes a proximal portion 1174 that remains exterior to thepatient and a distal potion 1176 that resides within the patientvasculature after placement is complete. The system 1110 is employed toultimately position a distal tip 1176A of the catheter 1172 in a desiredposition within the patient vasculature. In one embodiment, the desiredposition for the catheter distal tip 1176A is proximate the patient'sheart, such as in the lower one-third (⅓^(rd)) portion of the SuperiorVena Cava (“SVC”). Of course, the system 1110 can be employed to placethe catheter distal tip in other locations.

The catheter proximal portion 1174 further includes a hub 1174A thatprovides fluid communication between the one or more lumens of thecatheter 1172 and one or more extension legs 1174B extending proximallyfrom the hub. As mentioned, placement of a needle into the patientvasculature at the insertion site 1173 is typically performed prior toinsertion of the catheter, though it is appreciated that other placementmethods can be employed. Further, it is appreciated that the abovediscussion is only one example for use of the system 1110; indeed it canbe employed for a variety of uses, such as the placement of needlespreparatory to insertion of a catheter as above, the insertion of aneedle for other uses, or for the insertion of other medical componentsinto the body of a patient, including x-ray or ultrasound markers,biopsy sheaths, ablation components, bladder scanning components, venacava filters, etc.

In greater detail, the console 1120 houses a variety of components ofthe system 1110 and it is appreciated that the console can take one of avariety of forms. A processor 1122, including non-volatile memory suchas EEPROM for instance, is included in the console 1120 for controllingsystem function and executing various algorithms during operation of thesystem 1110, thus acting as a control processor. A digitalcontroller/analog interface 1124 is also included with the console 1120and is in communication with both the processor 1122 and other systemcomponents to govern interfacing between the probe 1140 and other systemcomponents.

The system 1110 further includes ports 1152 for connection withadditional components such as optional components 1154 including aprinter, storage media, keyboard, etc. The ports in one embodiment areUSB ports, though other port types or a combination of port types can beused for this and the other interfaces connections described herein. Apower connection 1156 is included with the console 1120 to enableoperable connection to an external power supply 1158. An internalbattery 1160 can also be employed, either with or exclusive of anexternal power supply. Power management circuitry 1159 is included withthe digital controller/analog interface 1124 of the console to regulatepower use and distribution.

The display 1130 in the present embodiment is integrated into theconsole 1120 and is used to display information to the clinician duringthe placement procedure, such as an ultrasound image of the targetedinternal body portion attained by the probe 1140. In another embodiment,the display may be separate from the console. In one embodiment, aconsole button interface 1132 and control buttons 1184 (FIG. 19)included on the probe 1140 can be used to immediately call up a desiredmode to the display 1130 by the clinician to assist in the placementprocedure. In one embodiment, the display 1130 is an LCD device.

FIG. 19 further depicts a needle 1200 used to gain initial access to thepatient vasculature via the insertion site 1173. As will be described infurther detail below, the needle 1200 is configured to cooperate withthe system 1110 in enabling the system to detect the position,orientation, and advancement of the needle during an ultrasound-basedplacement procedure.

FIG. 20 depicts features of the probe 1140 according to one embodiment.The probe 1140 is employed in connection with ultrasound-basedvisualization of a vessel, such as a vein, in preparation for insertionof the needle 1200 and/or catheter 1172 into the vasculature. Suchvisualization gives real time ultrasound guidance and assists inreducing complications typically associated with such introduction,including inadvertent arterial puncture, hematoma, pneumothorax, etc.

The handheld probe 1140 includes a head 1180 that houses a piezoelectricarray for producing ultrasonic pulses and for receiving echoes thereofafter reflection by the patient's body when the head is placed againstthe patient's skin proximate the prospective insertion site 1173 (FIG.19). The probe 1140 further includes a plurality of control buttons 1184(FIG. 19) for controlling the system, thus eliminating the need for theclinician to reach out of the sterile field, which is established aboutthe patient insertion site prior to establishment of the insertion site,to control the system 1110.

As such, in one embodiment a clinician employs the ultrasound imagingportion of the system 1110 to determine a suitable insertion site andestablish vascular access, such as with the needle 1200, prior tointroduction of the catheter 1172 for ultimate advancement thereofthrough the vasculature toward an intended destination.

FIG. 18 shows that the probe 1140 further includes a button and memorycontroller 1142 for governing button and probe operation. The button andmemory controller 1142 can include non-volatile memory, such as EEPROM,in one embodiment. The button and memory controller 1142 is in operablecommunication with a probe interface 1144 of the console 1120, whichincludes a piezo input/output component 1144A for interfacing with theprobe piezoelectric array and a button and memory input/output component1144B for interfacing with the button and memory controller 1142.

As seen in FIG. 20, the probe 1140 includes a sensor array 1190 fordetecting the position, orientation, and movement of the needle 1200during ultrasound imaging procedures, such as those described above. Aswill be described in further detail below, the sensor array includes aplurality of magnetic sensors 1192 embedded within the housing of theprobe. The sensors 1192 are configured to detect a magnetic fieldassociated with the needle 1200 and enable the system 1110 to track theneedle. Though configured here as magnetic sensors, it is appreciatedthat the sensors 1192 can be sensors of other types and configurations,as will be described. Also, though they are shown in FIG. 20 as includedwith the probe 1140, the sensors 1192 of the sensor array 1190 can beincluded in a component separate from the probe, such as a separatehandheld device. In the present embodiment, the sensors 1192 aredisposed in a planar configuration below a top face 1182 of the probe1140, though it is appreciated that the sensors can be arranged in otherconfigurations, such as in an arched or semi-circular arrangement.

In the present embodiment, each of the sensors 1192 includes threeorthogonal sensor coils for enabling detection of a magnetic field inthree spatial dimensions. Such three dimensional (“3-D”) magneticsensors can be purchased, for example, from Honeywell Sensing andControl of Morristown, N.J. Further, the sensors 1192 of the presentembodiment are configured as Hall-effect sensors, though other types ofmagnetic sensors could be employed. Further, instead of 3-D sensors, aplurality of one dimensional magnetic sensors can be included andarranged as desired to achieve 1-, 2-, or 3-D detection capability.

In the present embodiment, five sensors 1192 are included in the sensorarray 1190 so as to enable detection of the needle 1200 in not only thethree spatial dimensions (i.e., X, Y, Z coordinate space), but also thepitch and yaw orientation of the needle itself. Note that in oneembodiment, orthogonal sensing components of two or more of the sensors1192 enable the pitch and yaw attitude of the magnetic element 1210, andthus the needle 1200, to be determined.

In other embodiments, fewer or more sensors can be employed in thesensor array. More generally, it is appreciated that the number, size,type, and placement of the sensors of the sensor array can vary fromwhat is explicitly shown here.

FIGS. 21A and 21B show details of one example of the needle 1200 thatcan be used in connection with the guidance system 1110 in accessing atargeted internal body portion of the patient, as shown in FIG. 19,according to one embodiment. In particular, the needle 1200 includes ahollow cannula 1202, which defines a proximal end 1202A and a distal end1202B. A hub 1204 is attached to the proximal end 1202A of the cannula1202 and includes an open end 1204A that is configured as a connectorfor connecting with various devices, in the present embodiment. Indeed,the open end 1204A of the hub 1204 is in communication with the hollowcannula 1202 such that a guide wire, stylet, or other component may bepassed through the hub into the cannula.

As shown in FIGS. 21A and 21B, a magnetic element 1210 is included withthe hub 1204. As best seen in FIG. 21B, the magnetic element 1210 in thepresent embodiment is a permanent magnet, including a ferromagneticsubstance for instance, and is ring-shaped so as to define hole 1212that is aligned with the hollow cannula 1202. So configured, themagnetic element 1210 produces a magnetic field that is detectable bythe sensor array 1190 of the ultrasound probe 1140 so as to enable thelocation, orientation, and movement of the needle 1200 to be tracked bythe system 1110, as described further below.

In other embodiments, it is appreciated that many other types, numbers,and sizes of magnetic elements can be employed with the needle 1200 orother medical component to enable tracking thereof by the presentguidance system.

Reference is now made to FIGS. 22A and 22B, which show the ultrasoundprobe 1140 of the system 1110 and the needle 1200 in position and readyfor insertion thereof through a skin surface 1220 of a patient to accessa targeted internal body portion. In particular, the probe 1140 is shownwith its head 1180 placed against the patient skin and producing anultrasound beam 1222 so as to ultrasonically image a portion of a vessel1226 beneath the patient skin surface 1220. The ultrasonic image of thevessel 1226 can be depicted on the display 1130 of the system 1110 (FIG.19).

As mentioned above, the system 1110 in the present embodiment isconfigured to detect the position, orientation, and movement of theneedle 1200 described above. In particular, the sensor array 1190 of theprobe 1140 is configured to detect a magnetic field of the magneticelement 1210 included with the needle 1200. Each of the sensors 1192 ofthe sensor array 1190 is configured to spatially detect the magneticelement 1210 in three dimensional space. Thus during operation of thesystem 1110, magnetic field strength data of the needle's magneticelement 1210 sensed by each of the sensors 1192 is forwarded to aprocessor, such as the processor 1122 of the console 1120 (FIG. 18),which computes in real-time the position and/or orientation of themagnetic element 1210.

Specifically, and as shown in FIGS. 22A and 22B, the position of themagnetic element 1210 in X, Y, and Z coordinate space with respect tothe sensor array 1190 can be determined by the system 1110 using themagnetic field strength data sensed by the sensors 1192. Moreover, FIG.22A shows that the pitch of the magnetic element 1210 can also bedetermined, while FIG. 22B shows that the yaw of the magnetic elementcan be determined.

Suitable circuitry of the probe 1140, the console 1120, or othercomponent of the system can provide the calculations necessary for suchposition/orientation. In one embodiment, the magnetic element 210 can betracked using the teachings of one or more of the following U.S. Pat.Nos. 5,775,322; 5,879,297; 6,129,668; 6,216,028; and 6,263,230. Thecontents of the afore-mentioned U.S. patents are incorporated herein byreference in their entireties.

The above position and orientation information determined by the system1110, together with the length of the cannula 1202 and position of themagnetic element 1210 with respect to the distal needle tip as known byor input into the system, enable the system to accurately determine thelocation and orientation of the entire length of the needle 1200 withrespect to the sensor array 1190. Optionally, the distance between themagnetic element 1210 and the distal needle tip is known by or inputinto the system 1110. This in turn enables the system 1110 tosuperimpose an image of the needle 1200 on to an image produced by theultrasound beam 1222 of the probe 1140. FIGS. 23A and 23B show examplesof such a superimposition of the needle onto an ultrasound image.Specifically, FIGS. 23A and 23B each show a screenshot 1230 that can bedepicted on the display 1130 (FIG. 19), for instance. In FIG. 23A, anultrasound image 1232 is shown, including depiction of the patient skinsurface 1220, and the subcutaneous vessel 1226. The ultrasound image1232 corresponds to an image acquired by the ultrasound beam 1222 shownin FIGS. 22A and 22B, for instance.

The screenshot 1230 further shows a needle image 1234 representing theposition and orientation of the actual needle 1200 as determined by thesystem 1110 as described above. Because the system is able to determinethe location and orientation of the needle 1200 with respect to thesensor array 1190, the system is able to accurately determine theposition and orientation of the needle 1200 with respect to theultrasound image 1232 and superimpose it thereon for depiction as theneedle image 1234 on the display 1130. Coordination of the positioningof the needle image 1234 on the ultrasound image 1232 is performed bysuitable algorithms executed by the processor 1122 or other suitablecomponent of the system 1110.

The sensors 1192 are configured to continuously detect the magneticfield of the magnetic element 1210 of the needle 1200 during operationof the system 1110. This enables the system 1110 to continuously updatethe position and orientation of the needle image 1234 for depiction onthe display 1130. Thus, advancement or other movement of the needle 1200is depicted in real-time by the needle image 1234 on the display 1130.Note that the system 1110 is capable of continuously updating both theultrasound image 1232 and the needle image 1234 on the display 1130 asmovements of the probe 1140 and the needle 1200 occur during a placementprocedure or other activity.

FIG. 23A further shows that in one embodiment the system 1110 can depicta projected path 1236 based on the current position and orientation ofthe needle 1200 as depicted by the needle image 1234. The projected path1236 assists a clinician in determining whether the current orientationof the needle 1200, as depicted by the needle image 1234 on the display1130, will result in arriving at the desired internal body portiontarget, such as the vessel 1226 shown here. Again, as the orientationand/or position of the needle image 1234 changes, the projected path1236 is correspondingly modified by the system 1110. A target 1238,indicating the point where the projected path 1236 crosses the plane ofthe ultrasound image 1232, can also be depicted on the display 1130 bythe system 1110. As shown in FIG. 23A, in the present example the target1238 is located within the vessel 1226 depicted in the ultrasound image1232. Note that the position of the target 1238 on the display 1130 canalso be modified as the needle 1200 and/or the ultrasound image 1232 areadjusted. The screenshot 1230 also includes an area of probability 1239,here depicted as a box, which indicates any possible margin of error ofthe system due to needle length, needle rigidity and flex, fieldstrength of the magnetic element, magnetic interference, possiblediscrepancy in alignment of the magnetic axis of the magnetic elementwith the longitudinal axis of the needle, orientation of the sensorarray with respect to the ultrasound imaging plane, etc.

FIG. 23B shows that, in one embodiment, the screenshot 1230 can beconfigured such that the ultrasound image 1232 and the needle image 1234are oriented so as to be displayed in a three dimensional aspect. Thisenables the angle and orientation of the needle 1200, as depicted by theneedle image 1234, to be ascertained and compared with the intendedtarget imaged by the ultrasound image 1232. It should be noted that thescreenshots 1230 are merely examples of possible depictions produced bythe system 1110 for display; indeed, other visual depictions can beused. Note further that the particular area of the body being imaged ismerely an example; the system can be used to ultrasonically image avariety of body portions, and should not be limited to what isexplicitly depicted in the accompanying figures. Further, the system asdepicted and described herein can be included as a component of a largersystem, if desired, or can be configured as a stand-alone device. Also,it is appreciated that, in addition to the visual display 1130, auralinformation, such as beeps, tones, etc., can also be employed by thesystem 1110 to assist the clinician during positioning and insertion ofthe needle into the patient.

As mentioned above, in one embodiment it is necessary for the system1110 to know the total length of the needle 1200 and the location of themagnetic element 1210 thereon in order to enable an accurate depictionof the needle image 1234 and other features of the screenshots 1230 ofFIGS. 23A and 23B to be made. The system 1110 can be informed theseand/or other pertinent parameters in various ways, including scanning bythe system of a barcode included on or with the needle, the inclusion ofa radiofrequency identification (“RFID”) chip with the needle forscanning by the system, color coding of the needle, manual entry of theparameters by the clinician into the system, etc. For instance, an RFIDchip 1354 is included on the needle 1200 shown in FIG. 33A. The probe1140 or other component of the system 1110 can include an RFID reader toread the information included on the RFID chip 1354, such as the type orlength of the needle 1200, etc. These and other means for inputting theneedle parameters into the system 1110 or detecting the parameters aretherefore contemplated.

In one embodiment, a length of the needle (or other aspect of a medicalcomponent) can be determined by measurement by the probe/system of acharacteristic of the magnetic element, such as its field strength. Forinstance, in one embodiment the magnetic element of the needle can bepositioned at a predetermined distance from the probe or at apredetermined location with respect to the probe. With the magneticelement so positioned, the sensor array of the probe detects andmeasures the field strength of the magnetic element. The system cancompare the measured field strength with a stored list of possible fieldstrengths corresponding to different lengths of needles. The system canmatch the two strengths and determine the needle length. The needlelocation and subsequent needle insertion can then proceed as describedherein. In another embodiment, instead of holding the magnetic elementstationary at a predetermined location, the magnetic element can bemoved about the probe such that multiple field strength readings aretaken by the probe. Aspects that can be modified so as to impartdifferent field strengths to a set of magnetic element include size,shape, and composition of the magnetic element, etc.

Further details are given here regarding use of the system 1110 inguiding a needle or other medical device in connection with ultrasonicimaging of a targeted internal body portion (“target”) of a patient,according to one embodiment. With the magnetic element-equipped needle1200 positioned a suitable distance (e.g., two or more feet) away fromthe ultrasound probe 1140 including the sensor array 1190, the probe isemployed to ultrasonically image, for depiction on the display 1130 ofthe system 1110, the target within the patient that the needle isintended to intersect via percutaneous insertion. A calibration of thesystem 1110 is then initiated, in which algorithms are executed by theprocessor 1122 of the console 1120 to determine a baseline for anyambient magnetic fields in the vicinity of where the procedure will beperformed. The system 1110 is also informed of the total length of theneedle 1200, and/or position of the magnetic element with respect to thedistal needle tip such as by user input, automatic detection, or inanother suitable manner, as has been discussed above.

The needle 1200 is then brought into the range of the sensors 1192 ofthe sensor array 1190 of the probe 1140. Each of the sensors 1192detects the magnetic field strength associated with the magnetic element1210 of the needle 1200, which data is forwarded to the processor 1122.In one embodiment, such data can be stored in memory until needed by theprocessor. As the sensors 1192 detect the magnetic field, suitablealgorithms are performed by the processor 1122 to calculate a magneticfield strength of the magnetic element 1210 of the needle 1200 atpredicted points in space in relationship to the probe. The processor1122 then compares the actual magnetic field strength data detected bythe sensors 1192 to the calculated field strength values. Note that thisprocess is further described by the U.S. patents identified above. Thisprocess can be iteratively performed until the calculated value for apredicted point matches the measured data. Once this match occurs, themagnetic element 1210 has been positionally located in three dimensionalspace. Using the magnetic field strength data as detected by the sensors1192, the pitch and yaw (i.e., orientation) of the magnetic element 1210can also be determined. Together with the known length of the needle1200 and the position of the distal tip of the needle with respect tothe magnetic element, this enables an accurate representation of theposition and orientation of the needle can be made by the system 1110and depicted as a virtual model, i.e., the needle image 1234, on thedisplay 1130. Note that the predicted and actual detected values mustmatch within a predetermined tolerance or confidence level in oneembodiment for the system 1110 to enable needle depiction to occur.

Depiction of the virtual needle image 1234 of the needle 1200 asdescribed above is performed in the present embodiment by overlaying theneedle image on the ultrasound image 1232 of the display 1130 (FIGS.23A, 23B). Suitable algorithms of the system 1110 as executed by theprocessor 1122 or other suitable component further enable the projectedpath 1236, the target 1238, and area of probability 1239 (FIGS. 23A,23B) to be determined and depicted on the display 1130 atop theultrasound image 1232 of the target. The above prediction, detection,comparison, and depiction process is iteratively performed to continuetracking the movement of the needle 1200 in real-time.

In light of the foregoing and with reference to FIG. 24, it isappreciated that in one embodiment a method 1240 for guiding a needle orother medical component includes various stages. At stage 1242, atargeted internal body portion of a patient is imaged by an imagingsystem, such as an ultrasound imaging device for instance.

At stage 1244, a detectable characteristic of a medical component suchas a needle is sensed by one or more sensors included with the imagingsystem. In the present embodiment, the detectable characteristic of theneedle is a magnetic field of the magnetic element 1210 included withthe needle 1200 and the sensors are magnetic sensors included in thesensor array 1190 included with the ultrasound probe 1140.

At stage 1246, a position of the medical component with respect to thetargeted internal body portion is determined in at least two spatialdimensions via sensing of the detectable characteristic. As describedabove, such determination is made in the present embodiment by theprocessor 1122 of the console 1120.

At stage 1248, an image representing the position of the medicalcomponent is combined with the image of the targeted internal bodyportion for depiction on a display. Stage 1250 shows that stages1244-1248 can be iteratively repeated to depict advancement or othermovement of the medical component with respect to the imaged target,such as percutaneous insertion of the needle 1200 toward the vessel 1226(FIGS. 23A, 23B), for instance.

It is appreciated that the processor 1122 or other suitable componentcan calculate additional aspects, including the area of probability 1239and the target 1238 (FIGS. 23A, 23B) for depiction on the display 1130.

It is appreciated that in one embodiment the sensor array need not beincorporated natively into the ultrasound imaging device, but can beincluded therewith in other ways. FIG. 25 shows one example of this,wherein an attachable sensor module 1260 including the sensors 1192 ofthe sensor array 1190 is shown attached to the ultrasound probe 1140.Such a configuration enables needle guidance as described herein to beachieved in connection with a standard ultrasound imaging device, i.e.,a device not including a sensor array integrated into the ultrasoundprobe or a processor and algorithms configured to locate and track aneedle as described above. As such, the sensor module 1260 in oneembodiment includes a processor and algorithms suitable for locating andtracking the needle or other medical component and for depicting on adisplay the virtual image of the needle for overlay on to the ultrasoundimage. In one embodiment, the sensor module 1260 can be included with amodule display 1262 for depiction of the needle tracking. These andother configurations of the guidance system are therefore contemplated.

FIG. 26 shows that in one embodiment, a needle holder can be employed tohold and advance the needle 1200 during the ultrasound imaging andneedle guidance procedure performed by the system 1110 as has beendescribed. As shown, the needle holder 1270 is pistol-shaped andincludes a trigger 1272 for selectively advancing the needle 1200 orother suitable medical component by moving the needle longitudinallyaway from the barrel of the holder upon pressing of the trigger. Soconfigured, the needle holder 1270 facilitates ease of needle handlingwith one hand of the clinician while the other hand is grasping andmanipulating the ultrasound probe 1140. In addition, the needle holder1270 can provide needle movement/rotation assistance such as via amotor, ratcheting, hydraulic/pneumatic drivers, etc. Moreover, aclocking feature can be included on the needle holder 1270 to assistwith determining the orientation of the distal tip of the needle 1200and for facilitating rotation of the needle.

In one embodiment, the needle holder 1270 can be operably connected tothe system 1110 such that advancement by the needle holder isautomatically stopped when the distal end 1202B of the needle cannula1202 reaches the targeted internal body portion or the needle interceptsthe ultrasound plane. In yet another embodiment the magnetic element canbe included with the needle holder instead of the needle itself. Theneedle, when temporarily attached to the needle holder, can thus belocated and guided by the guidance system without the need for amagnetic element to be attached directly to the needle.

Note that other sensor configurations can also be employed. In oneembodiment, an annular sensor can be configured to receive through ahole defined thereby the cannula of the needle. So disposed, a magneticelement of the needle is positioned proximate the annular sensor, whichenables ready detection of the magnetic element and location of theneedle by the system. The annular sensor can be attached to a surface ofthe probe, in one embodiment.

FIGS. 27 and 28 depict components of the guidance system 1110 accordingto another embodiment, wherein an optical-based interaction between theprobe 1140 and the needle 1200 is employed to enable tracking andguidance of the needle. In particular, the probe 1140 includes aoptical/light source, such as an LED 1280, and a photodetector 1282positioned on the probe surface. It is appreciated that the light sourceand detector can be configured to produce and detect light signals of avariety of ranges including visible, infrared, etc.

The needle hub 1204 includes a reflective surface 1286 capable ofreflecting light produced by the LED 1280 and incident thereon. As shownin FIG. 28, light emitted by the LED 1280 is reflected by the reflectivesurface 1286 of the needle 1200, a portion of which is received andsensed by the photodetector 1282. As in previous embodiments, theprocessor 1122 of the system console 1120 can be employed to receive thesensed data of the photodetector 1282 and compute the position and ororientation of the needle 1200. As before, the length of the needle 1200and/or the position of the reflective surface with respect to the distalend of the needle 1200 are input into or otherwise detectable or knownby the system 1110. Note that the reflective surface can be included atother locations on the needle.

In light of the above, it is appreciated that in the present embodimentthe detectable characteristic of the needle 1200 includes thereflectivity of the reflective surface 1286, in contrast to the magneticfield characteristic of the magnetic element 1210 of previousembodiments, and the sensor includes the photodetector 1282, in contrastto the magnetic sensors 1192 of previous embodiments. It should beappreciated that in one embodiment, the above-described configurationcan be reversed, wherein an optical source is included with the needleor medical component. In this case, light is emitted from the needle anddetected by the photodetector 1282 included with the probe 1140 so as toenable location and tracking of the needle. A power source can beincluded with the needle, such as a watch battery or the like, in orderto power the light source of the needle.

More generally, it is appreciated that the needle or medical componentcan include one or more of these or other detectable characteristics toenable the needle to be tracked and guided toward a target within thebody of the patient. Non-limiting examples of other detectablecharacteristic modalities include electromagnetic or radiofrequency(“RF”) (see, e.g., FIGS. 29-30 below), and radioactivity. With respectto RF modalities, it is appreciated that one or more synchronously orasynchronously pulsed frequency sources can be included with the needleas to enable detection thereof by a suitable sensor(s). Or, an RF firstsource can be coupled with a passive magnet as a second source.

FIGS. 29 and 30 depict components of a guidance system according to oneembodiment, wherein EM signal interaction between the probe 1140 and theneedle 1200 is employed to enable tracking and guidance of the needle.In particular, in FIG. 29 the needle 1200 includes a stylet 1298disposed therein. The stylet 1298 includes an EM coil 1290 that isoperably connected to the probe 1140 via a tether 1292. In this way, theEM coil 1290 can be driven by suitable components included in the probe1140 or system console 1120 such that the EM coil emits an EM signalduring operation.

A sensor 1294 suitable for detecting EM signals emitted by the EM coil1290 of the stylet 1298 is included in the probe 1140. In the presentembodiment, the sensor 1294 is a three-axis sensor for detectingcorresponding orthogonal components of the EM signal, though other coiland sensor configurations can also be employed. So configured, theposition and orientation of the needle 1200 can be determined, by EMsignal triangulation or other suitable process, and displayed by thesystem in a manner similar to that already described above. As inprevious embodiments, the processor 1122 of the system console 1120(FIG. 18) can be employed to receive the sensed data of the EM sensor1294 and compute the position and/or orientation of the needle 1200. Asbefore, the length of the needle 1200 and/or the position of the EM coil1290 with respect to the distal end of the needle 1200 are input into orotherwise detectable or known by the system.

FIG. 30 shows a variation of the EM configuration of FIG. 29, whereinthe respective positions of the EM components is reversed: the EM coil1290 is included in the probe 1140 and the EM sensor 1294 is includedwith the stylet 1298 disposed in the needle 1200. Note that in theembodiments of FIGS. 29 and 30, the operable connection between the EMcoil 1290 and the EM sensor 1294 via the tether 1292 enables thecomponent disposed in the stylet 1298 to be driven by the system 1110.This also enables correspondence of the particular EMfrequency/frequencies emitted by the EM coil 1290 and detected by the EMsensor 1294 to be made. In one embodiment, the configuration shown inFIG. 29 can be varied, wherein no tether operably connects the EM coiland the EM sensor; rather, the EM coil of the stylet operates as aseparate component from the probe and its EM sensor and is powered by anindependent power source, such as a battery. In this case, theprobe/system includes suitable signal processing components configuredto detect the EM signal emitted by the EM coil and to process it asnecessary in order to locate the needle.

Note that the EM coil and EM sensors can be included at other locationsthan what is depicted herein. For instance, the EM coil can be includedon the needle itself, or on a connector that is attachable to theproximal end of the needle.

FIGS. 31A-31D give further details of the needle 1200 configuredaccording to one embodiment, wherein the needle includes a hub 1304 fromwhich extends the cannula 1202. A magnetic element 1310 defining a hole1312 is included in a cavity 1314A of a housing 1314. The housing 1314includes threads so as to threadably engage the needle hub 1304 or othersuitable component of the needle or medical component. In this way, themagnetic element 1310 is removably attachable to the needle 1200 via thehousing 1314. Thus, the magnetic element 1310 need not be permanentlyaffixed or included with the needle 1200, but rather can be removedtherefrom when magnetic-based needle guidance is no longer needed. Inaddition, this enables the magnetic element to be attached to manydifferent types and sizes of needles. Note that in the presentembodiment the needle 1200 further includes a distally slidable needlesafety component 1320 for safely isolating the distal tip of the needleupon removal of the needle from the patient. Note further that otherremovable magnetic elements can be employed in addition to what isexplicitly shown and described herein.

FIGS. 32-33B give further examples of the needle 1200 including amagnetic element. In FIG. 32, two bar-like magnetic elements 1340 aredisposed so as to orthogonally extend from a hub 1334 of the needle1200, illustrating that the magnetic element need not be orientedparallel to the longitudinal axis of the needle. In FIGS. 33A-33B, fourmagnetic elements 1350 are included in the needle hub 1344, showing thatmore than one magnetic element can be included with the needle. Such aconfiguration may be employed, for example, where limited space preventsone magnetic element from being used. Note the number, shape, andplacement of the magnetic elements here is only one example of manypossible configurations.

FIGS. 34A-34G give various example configurations of a magnetic element1360 that defines a hole for receiving the cannula of the needletherethrough. Various shape configurations for the magnetic element 1360are shown, including a square (FIG. 34A), a hexagon (FIG. 34B), atriangle (FIG. 34C), a rectangle (FIG. 34D), an oval (FIG. 34E), anoctagon (FIG. 34F), and a four-sided pyramid (FIG. 34G). The magneticelements shown in the accompanying figures are merely examples of thebroad number of geometric and other shapes that can be used to definethe magnetic element; indeed other shapes not shown explicitly hereinare also contemplated.

FIGS. 35 and 36 depict yet another embodiment, wherein a stylet 1390 isincluded for removable insertion into the hollow cannula 1202 of theneedle 1200. A plurality of permanent magnets 1392, such as solid,cylindrically shaped ferromagnets stacked end-to-end with each other, isincluded at a distal end of the stylet 1390. As shown in FIG. 36, thestylet 1390 is received within the needle cannula 1202 during insertionof the needle 1200 into the patient. A sensor ring 1396 or othersuitable magnetic sensor can be included with or in proximity to theprobe 1140 to enable detection of the magnetic field of the magnets1392, thus enabling the guidance system to detect the position andorientation of the needle 1200 and superimpose an image thereof atop theultrasound image produced by the probe 1140 in a manner similar to thatdescribed in connection with FIGS. 5A-7.

FIGS. 35 and 36 thus illustrate that the magnetic element(s) can beconfigured in any one of a variety of ways. In one embodiment, forexample, the magnetic elements can be disposed more proximally along thestylet length. In another embodiment, the stylet itself can bemagnetized or composed of magnetic materials. It is appreciated that thestylet can be configured in one of many different ways, analogousexamples of which can be found in U.S. Pat. No. 5,099,845, titled“Medical Instrument Location Means,” and U.S. Patent ApplicationPublication No. 2007/0049846, filed Aug. 23, 2006, titled “StyletApparatuses and Methods of Manufacture,” both of which are incorporatedherein by reference in their entireties. These and other variations aretherefore contemplated.

It should be appreciated herein that “stylet” as used herein can includeany one of a variety of devices, including guidewires, configured forremovable placement within a lumen of the needle to assist in theplacement thereof within the patient. In one embodiment, the stylet caninclude a sharp end that distally extends past a blunt distal end of theneedle cannula so as to enable a blunt needle to be inserted into apatient. Note that the stylet in one embodiment stiffens the needle soas to minimize unintended bending thereof during insertion.

FIG. 37 depicts yet another possible embodiment, wherein the needle 1200includes an annular or donut-shaped magnet 1400 disposed distal to aproximal end 1202A of the needle cannula 1202. Note that the magnet 1400can be positioned in one of several positions along the length of thecannula 1202, in other embodiments. Positioning of the magnet 1400relatively closer to the distal needle tip reduces the effects thatunintended bending of the needle has on determining and displaying theposition of the needle. In yet another embodiment, the needle itself canbe magnetized. Note further that the relative places of the sensor andsource (e.g., magnet) of the system can be reversed. These and otherconfigurations are also contemplated. Further, note that the discussionherein can be applied to other imaging modalities in addition toultrasound, including MRI, x-ray and CT scanning, etc.

FIG. 38 depicts a strain gauge 1410 included on a stylet, such as thestylet 1390 shown in FIGS. 35 and 36 for instance. The strain gauge 1410can be operably connected to the probe 1140, console 1120 (FIG. 18), orother component of the system 1110 via a conductive path 1414. Oneexample of the conductive path 1414 includes one or more conductivewires disposed in or along the stylet 1390, for instance. So connected,the strain gauge 1410 acts as a transducer and can provide data relatingto bending of the needle in which the stylet 1390 is disposed duringneedle insertion procedures, given that bending of the needle 1200 willcause similar bending to occur in the stylet 1390.

These data sensed via bending of the strain gauge 1410 can be forwardedto and interpreted by the processor 1122 (FIG. 18) or other suitablecomponent of the system 1110 so as to include such bending together withdetection of the magnetic element by the probe sensors 1192 (FIG. 20) incomputing the position of the needle 1200, especially the distal tipthereof. This results in enhanced accuracy for locating and depictingthe position of the needle distal tip. Indeed, FIG. 39A shows flexure ofthe strain gauge 1410 in one direction as caused by bending of thestylet 1390, wherein FIG. 39B shows flexure of the strain gauge inanother direction. Such stylet bending is thus detected by the straingauge 1410 (via changes in electrical resistance within the strain gaugein one embodiment) and forwarded to the system 1110 for use in computingneedle position. Note that other suitable sensors and gauges canoptionally be used for measuring needle/stylet bending, including a flexsensor 1420, as shown in FIG. 40 for instance, and capacitance and fiberoptic-based strain gauges/sensors. Also, the sensor/gauge may be placeddirectly on the needle/medical component, in one embodiment.

Embodiments of the invention may be embodied in other specific formswithout departing from the spirit of the present disclosure. Thedescribed embodiments are to be considered in all respects only asillustrative, not restrictive. The scope of the embodiments is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A guidance system, comprising: an ultrasound imaging probe forultrasonically imaging an internal body portion target; a medical deviceseparate from the imaging probe configured for insertion into theinternal body portion target, the medical device having a magnetic fieldassociated therewith; one or more sensors associated with the probe thatsense the magnetic field; a processor that uses data relating to themagnetic field sensed by the one or more sensors to determine a positionand/or orientation of the medical device; and a display that shows animage of the internal body portion target taken by the ultrasoundimaging probe and a depiction of the medical device positioned and/ororiented with respect to the image.
 2. The guidance system according toclaim 1, wherein the medical device is a needle, and the internal bodyportion target is a blood vessel.
 3. The guidance system according toclaim 1, wherein the magnetic field is provided by a magnetic elementcoupled to the medical device.
 4. The guidance system according to claim3, wherein the magnetic element is a permanent magnet.
 5. The guidancesystem according to claim 1, wherein the medical device is magnetized,the magnetized medical device providing the magnetic field.
 6. Theguidance system according to claim 5, wherein the medical device is aneedle or a cannula.
 7. The guidance system according to claim 1,wherein the at least one sensor comprises a plurality of magneticsensors embedded within a housing of the probe.
 8. The guidance systemaccording to claim 7, wherein each of the magnetic sensors is configuredfor detection of a magnetic field in three spatial dimensions.
 9. Theguidance system according to claim 8, wherein each of the magneticsensors includes orthogonal sensor coils.
 10. The guidance systemaccording to claim 7, wherein the magnetic sensors are configured tocontinuously detect the magnetic field, and wherein the system isconfigured to continuously update the ultrasound image, such that theposition and/or orientation of the medical device with respect to theimage of the internal body portion target is continuously updated assimultaneous movements of the probe and the medical device occur.
 11. Aguidance system, comprising: an ultrasound imaging probe; a plurality ofmagnetic sensors; a needle having a magnetic field associated therewith;a processor configured for using data relating to the magnetic field todetermine a position and orientation of the needle; and a display thatshows an image taken by the ultrasound imaging probe and a depiction ofthe needle positioned and oriented relative to the image.
 12. Theguidance system according to claim 11, wherein the needle is magnetized,the magnetized needle providing the magnetic field.
 13. The guidancesystem according to claim 11, wherein the magnetic field is provided bya magnetic element coupled to the needle.
 14. The guidance systemaccording to claim 13, wherein the magnetic element is a permanentmagnet.
 15. The guidance system according to claim 11, wherein theplurality of magnetic sensors are associated with the ultrasound imagingprobe.
 16. The guidance system according to claim 15, wherein theplurality of magnetic sensors are embedded within a housing of theprobe.
 17. The guidance system according to claim 11, wherein each ofthe magnetic sensors is configured for detection of a magnetic field inthree spatial dimensions.
 18. The guidance system according to claim 17,wherein each of the magnetic sensors includes orthogonal sensor coils.19. The guidance system according to claim 11, wherein the magneticsensors are configured to continuously detect the magnetic field, andwherein the system is configured to continuously update the image, suchthat the position and orientation of the medical device relative to theimage is continuously updated as simultaneous movements of theultrasound imaging probe and the needle occur.